Shoe sole



Sept. 17, 1963 H. c. KNELLWOLF SHOE SOLE Filed Sept. 1, 1961 IIIII IIIIIIIII INVENTOR HANS C KNELLWOLF mkmls 5- ATTORNEYS United States Patent 3,103,931 SHOE SOLE Hans C. Kneliwolf, Heldenbachstr. 21, Zurich, Switzerland Filed Sept. 1, 1961, Ser. No. 135,592 Claims priority, application Switzerland Sept. 3, 1960 1 Claim. (Cl. 128582) This invention relates to a shoe sole and refers more particularly to a sole which has various therapeutic and muscle-building properties.

It is a matter of general knowledge that the best way of preventing deformation of feet is to strengthen muscles and ligaments. The most natural therapy for this purpose consists of providing unrestricted action of muscles during walking, particularly in walking barefoot upon a yieldable ground. These power-developing feet movements are greatly restricted by the shoes now in use. The supporting tissues of the foot relax too much due to the lack of intensive activity of the muscles, and the result is a weak foot and later a deformed foot. Thus there is no doubt that in order to preserve a healthy foot the shoe must provide suflicient freedom of movement for the foot, and particularly the shoe must make it possible for the foot to develop therein according to its natural tendencies. Only when the structure of a shoe will be improved to the extent that the foot will be able to carry out therein the normal actuation of muscles, such as takes place when going barefoot, will it be possible for the feet to be strengthened so that they will be capable of supporting the weight of the body without damage. However, the normal activity of foot muscles does not depend only on the freedom of movement of the foot, but also upon the nature of the surface supporting the foot.

In prior art many suggestions were made to improve the use of shoes in walking, taking into consideration the fact that the civilized man is usually required to walk upon a hard surface; such suggestions included the use of inserts of foam rubber, foot supports or built-in shoe parts of foam rubber, soft heel cushions, porous rubber soles, inflated soles etc. All these auxiliary means have the purpose of making walking more elastic, but they have no effect upon the action of the muscles. Socalled corrective shoes are also known, which are shaped to provide normal position for the toes, furthermore shoes with distortable joints and very flexible soles, which provide little resistance to the rolling movement of the foot. There are also shoes or shoe soles wherein the surface engaged by the toes consists of soft material so as to provide additional bending movements for the toes, etc. All these suggestions and auxiliary articles constitute, however, one-sided measures. They either serve the purpose of providing elastic walking upon hard ground, or they provide additional bending movements for the toes during walking so as to strengthen muscles controlling the bending of toes. None of these articles can improve the entire functioning of the toot in the shoe, since always only a part of groups of muscles is stimulated to more active exertion. For example, it is not sufficient to strengthen the bending muscles of toes by providing for a deeper engagement of the toes, since the toe bending muscles constitute only a small part of forces maintaining the foot arch.

For example, walking barefoot on a beach, namely upon wet sand, is normal and pleasant. During such Walking one can feel how intensely each foot muscle is alternately actuated. There are the following two features which are remarkable during such Walking:

(1) The heel is deeply impressed into the ground while at the same time lumps of sand are shifted under the metatarsus.

(2) The deep engagement of toes follows immediately thereafter.

The pressing of the heel and the deep engagement of the toes which follows practically immediately thereafter, cause a high bending of the metatarsus, namely, an active raising of the longitudinal arch in which participate not only the toe bending muscles, but to an even greater extent the front and rear shin bone muscles, as well as the calf muscles.

An object of the present invention is to provide means to enable a foot to walk in a shoe in such manner that following the above described example of walking upon wet sand, substantially all muscle groups of the foot are caused to function, including the raising muscles of the metatarsus which were disregarded heretofore.

Other objects of the present invention will become apparent in the course of the following specification.

In accomplishing the objects of the present invention it was found desirable to provide a shoe sole wherein the supporting surface for the heel and for the front portion of the foot consists of soft, elastically yieldable material, while the supporting surface for the metatarsus consists of a harder material, for the purpose of providing an active raising of the metatarsus during the walking movements of the foot.

In this connection it is advantageous when in the front not only the surface supporting the heads of toes is soft, but also that supporting the toe balls. Since they will then sink, in more deeply, the movement in the joints is increased between the tarsus and the metatarsal bones with the result that there is increased activity of the lower calf muscles which terminate at the metatarsus.

The sole of the present invention is particularly suitable for sandals used in foot gymnastics; however, the sole constituting the present invention can be used in connection with ordinary shoes, by incorporating in a shoe the elastic foot support of this invention or by the use of a corresponding elastic sole insert.

The invention will appear more clearly from the following detailed description when rtaken in connection with the accompanying drawing showing, by way of example, preferred embodiments of the inventive idea.

In the drawing:

FIGURE 1 is a longitudinal section through a sandal provided wtih the elastic foot support of the present invention.

FIGURE 2 is a longitudinal section through a sole which may be incorporated into a shoe as a base thereof.

FIGURE 3 is a top View of the sole shown in FIG. 2.

FIGURE 4 is a longitudinal section through a sole of the present invention which may be used as a removable insert in connection with any existing shoe.

FIGURE 1 illustrates a sandal having a sole constituting an elastic foot support and including a middle portion 1 which is made of harder material, such as leather or compressed cork, and a front portion 2 as well as a rear or heel portion 3 which are both made of porous material, such as foam rubber. The upper side of the middle portion 1 is shaped so that it constitutes a support for the metatarsus. The middle portion 1 is raised in the center and extends substantially wedge-like forwardly and rearward-1y. The elastic front and rear portions 2 and 3 are shaped so that they complete the foot support and are provided with wedge-shaped ends extending to the raised pant of the middle portion 1. The elastic sole which is thus formed is enclosed in the usual manner in a leather cover 4 and is mounted upon the base 5.

The elastic sole which is shown in FIGURES 2 and 3 and which can serve as the built-in base of a shoe, is also provided with a middle portion 1a of leather or compressed cork, which extends wedge-like forwardly and rearwardly and which has a raised central part serving as a support for the raising of the metatarsus. The (front portion 2a and the rear portion 3a, which may be made of foam rubber, have wedge-like ends extending to said central part.

FIGURE 4 illustrates an elastic sole insert having a harder middle portion 1b and softer front and rear portions 2b and 3b. The insert is comparatively thin since it is to be used in rea dymade shoes.

It is apparent that the examples shown above have been given solely by Way of illustration and not by Way of limitation and that they are capable of many variations and modifications within the scope of the present invention. All such variations and modifications are to be included Within the scope of the present invention.

What is claimed is:

A shoe sole, comprising a comparatively hand middle portion having an outwardly curved central part extending completely from one side to the opposite side of the sole for :directly supporting the metatarsus of a foot, and wedge-like end parts extending tforwardly and rear'wardly of said central part, a rear portion consisting of soft, elas tically yieldable material tor directly supporting the heel of the foot, said rear portion being wedge-shaped and located over the rearwardly extending wedge-like end part of said middle portion, said rear portion extending completely from one side to the opposite side of the sole and having outer edges enveloping the heel-carrying portion of the sole, and a lfiront portion consisting of soft, elastically yieldable material for directly supporting the toes and the toe balls of the :foot, said front portion being wedge-shaped and located over the forwardly extending wedge-like end part of said middle portion said front portion extending completely [from one side to the opposite side of the sole and having outer edges enveloping the toe and toe ball-carrying portion of the sole, said soft t'ront and rear portions being separated by said hard portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,743,648 Appleton Jan. 14, 1930 1,841,942 Fenton Jan. 19, 1932 1,843,952 McBrearty Feb. 9, 1932 2,486,653 Hukill Nov. 1, 1949 2,710,462 Swadburgh June 14, 1955 

